Topological analysis of energy hypersurface

1980 ◽  
Vol 45 (9) ◽  
pp. 2463-2473 ◽  
Author(s):  
Jiří Pancíř
Keyword(s):  
Total Energy ◽  
Chemical Reactions ◽  
Reaction Mechanisms ◽  
Driving Force ◽  
Topological Analysis ◽  
Matrix Elements ◽  
Qualitative Information ◽  
Linear Change ◽  
Hartree Fock ◽  
Energy Hypersurface

Topological approximations discussed in the preceeding paper are used for construction of topological energy hypersurfaces of chemical reactions on two levels of a sophistication. A method of a linear change of off diagonal matrix elements reproduces adequately Woodward-Hoffmann rules but it provides only qualitative information about energetical relations. A physically more rigorous hypothesis where the reaction driving force is a function of hybridization changes at reaction sites provides energy hypersurfaces which are correct from a quantitative viewpoint. The method suggested treats the total energy as a function of abstract reaction angles which reflect topological changes accompanying the reaction course. A reaction mechanisms analysis leads then to the analysis of topological energy hypersurfaces which can be treated similarly to that of conventional geometrical hypersurfaces. Formulas for atomic integrals necessary in the construction of Hartree-Fock and CI matrices are derived in the basis of reaction angles mentioned and approximations leading to the semiempirical type of a calculation are discussed.

scholarly journals The Principle of Conservation of Structural Aspect: Facilitating Visual Communication and Learning in Organic Chemistry Instruction

2019 ◽  
Author(s):  
john andraos
Keyword(s):  
Organic Chemistry ◽  
Chemical Reactions ◽  
Reaction Mechanisms ◽  
Visual Communication ◽  
Structural Aspect ◽  
Chemical Bonds ◽  
Journal Articles ◽  
Chemistry Instruction ◽  
Individual Reaction ◽  
Training Exercises

<p>An effective pedagogical method is presented for the visual communication of chemical reactions learned in organic chemistry undergraduate courses. The basis for the method is the preservation of the visual aspect of reactant and product structures so that the tracking of cleaved and formed chemical bonds is made self-evident. This consequently leads to improved clarity of presentation and a better understanding and grasp of proposed reaction mechanisms to explain product outcomes. The method is demonstrated for a variety of individual reaction types and synthesis plans. Various visual training exercises are also presented using ChemDraw Ultra 7.0 software and literature table of contents (TOC) graphics appearing in journal articles.</p><br>

Orbit–orbit interaction inn fN electron configurations

1969 ◽  
Vol 47 (17) ◽  
pp. 1885-1888 ◽  
Author(s):  
K. M. S. Saxena ◽  
G. Malli
Keyword(s):  
Orbit Interaction ◽  
Matrix Elements ◽  
Atomic Systems ◽  
Hartree Fock ◽  
The Matrix

The expressions of the matrix elements of the orbit–orbit interaction for various fN electron configurations are computed and tabulated for general usage. These expressions are used to evaluate the Hartree–Fock values of the orbit–orbit interaction in all the states for a large number of fN electron atomic systems.

GALVANIC CELLS AND THE DRIVING FORCE OF CHEMICAL REACTIONS

1968 ◽  
pp. 282-308
Author(s):  
AMOS TURK ◽  
HERBERT MEISLICH ◽  
FRANK BRESCIA ◽  
JOHN ARENTS
Keyword(s):  
Chemical Reactions ◽  
Driving Force ◽  
Galvanic Cells

Monitoring of chemical transformations by mass spectrometry

2015 ◽  
Vol 7 (17) ◽  
pp. 6947-6959 ◽  
Author(s):  
Chun-Chi Chen ◽  
Po-Chiao Lin
Keyword(s):  
Mass Spectrometry ◽  
Chemical Reactions ◽  
Reaction Mechanisms ◽  
Chemical Transformations

During the last several decades, mass spectrometry (MS) has rapidly developed as a practical technique that can be used to monitor chemical reactions and investigate reaction mechanisms.

Syneresis in Silica Gel

1988 ◽  
Vol 121 ◽  
Author(s):  
George W. Scherer
Keyword(s):  
Fluid Flow ◽  
Sample Size ◽  
Silica Gel ◽  
Chemical Reactions ◽  
Driving Force ◽  
Viscoelastic Behavior ◽  
Accurate Representation ◽  
Flow Through ◽  
Kinetics Of ◽  
Gel Network

ABSTRACTThe driving force for syneresis is generally attributed to the same chemical reactions that produce gelation, but it has also been proposed that shrinkage could be driven by interracial energy. The latter possibility is explored and discounted. The kinetics of syneresis depend on the driving force, the mobility of the gel network, and the rate of fluid flow through the contracting gel. A model that allows for viscoelastic behavior of the gel and fluid flow according to Darcy's law is shown to provide a quantitatively accurate representation of the shape of the shrinkage curves and the dependence of the shrinkage rate on sample size.

scholarly journals Nuclear transition matrix elements for neutrinoless double-β decay within mechanisms involving light Majorana neutrino mass and right-handed current

2019 ◽  
Vol 28 (01n02) ◽  
pp. 1950001
Author(s):  
Yash Kaur Singh ◽  
R. Chandra ◽  
K. Chaturvedi ◽  
Tripti Avasthi ◽  
P. K. Rath ◽  
...  
Keyword(s):  
Neutrino Mass ◽  
Transition Matrix ◽  
Weak Coupling ◽  
Majorana Neutrino ◽  
Nuclear Transition ◽  
Matrix Elements ◽  
Β Decay ◽  
Hartree Fock ◽  
Transition Matrix Elements ◽  
Majorana Neutrino Mass

Employing the projected-Hartree-Fock-Bogoliubov (PHFB) model in conjunction with four different parametrizations of pairing plus multipolar effective two-body interaction and three different parametrizations of Jastrow short-range correlations, nuclear transition matrix elements for the neutrinoless double-[Formula: see text] decay of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] isotopes are calculated within mechanisms involving light Majorana neutrino mass and right-handed current. Statistically, model specific uncertainties in sets of twelve nuclear transition matrix elements are estimated by calculating the averages along with the standard deviations. For the considered nuclei, the most stringent extracted on-axis limits on the effective light Majorana neutrino mass [Formula: see text], the effective weak coupling of right-handed leptonic current with right-handed hadronic current [Formula: see text], and the effective weak coupling of right-handed leptonic current with left-handed hadronic current [Formula: see text] from the observed limit on half-life [Formula: see text] of [Formula: see text] isotope are [Formula: see text][Formula: see text]eV, [Formula: see text] and [Formula: see text], respectively.

Sign in / Sign up

Export Citation Format

Share Document